Releasing arrangement for electric switches



llflll 4 Bl-IVETQLUC M1 fl Feb. 4, 1936. E

' RELEASING ARRANGEMENT FOR ELECTRIC SWITCHES Flled May 25 1934Bl-METflLL/G Patented Feb. 4, 1936 RELEASING ARRANGEMENT FOB ELECTRICSWITCHES Ernst Besag, Baden-Baden, Germany Application May 25, 1934,Serial No. 727,493 In Germany May, 26, 1933 13 Claims. (01.200-88) Oneof the most difflcult problems in the construction of electric switches,for example in the construction of protective switches for motors, isthe design of the thermal releasing arrangement. As a rule, each thermalreleasing device forms a separate constructional unit which is fittedseparately in the switch. This requires special'technlcal knowledgewhich the person who undertakes the exchanging of releasing devicesoften does not possess. The fitting and exchanging of releasing devicesis considerably simpler if all releasing devices of a switch arecombined to form a constructional unit which is connected with theswitch so as to be easily detachable, for example if they are mounted ona common plate or base. It has also already been proposed to enclose allthermal releasing devices separately from the remaining parts of theswitch in a common housing, in order, while permitting of an easymounting, to make them as far as possible inaccessible to inexpertpersons, for example by sealing the housing of the releasing device. Butall releasing arrangements wherein the releasing devices of all phasesare combined to form a constructional unit separately from the remainingparts of the switch, e. g. the switch contacts, the actuating magnet,and so on, occupy a great amount of space. I

The present invention solves the problem of providing a releasingarrangement of very small dimensions, wherein the thermal releasingdevices are enclosed in a housing that can be connected with diflerentswitches so as to be easily detachable, and which covers, in spite ofits smallness, a very great range of releasing current intensities, sothat it is only necessary to construct a few types of releasingarrangements according to this invention in order to cover a requiredtotal range of releasing current intensities.

According to this invention, the housing of the releasing arrangement,consisting of insulating material, is sub-divided into a plurality ofchambers whose number is greater by one than the number of releasingdevices present each of which is accommodated ,in a chamber, while inthe chamber notoccupied by a releasing device an arrangement for thecompensation of the influence of the room temperature on the releasingdevices and for adjusting the releasing path' of same is situated onwhich a releasing cross piece acts which passes through apertures in thepartitions which thermally and electrically insulate the releasingdevices with respect to one another and with respect to the compensatingand adjusting device.

Owing to the fact that in the case of the subject of the invention theindividual thermal releasing devices are separated from one another andfrom the compensating and adjusting device by insulating partitions,great surface leakage paths and great flash-over distances are producedbetween the parts lying under various potentials, in spite of the factthat the releasing devices and the aforesaid compensating and adjustingdevice closely approach one another. By reason of the fact that thepartitions thermally insulate the releasing devices with respect to oneanother it is brought about that one releasing device is not 5influenced by the adjacent releasing device. The consequence of allthermal releasing devices being thermally insulated with respect to thecompensating and adjusting device is that the latter lies approximatelyat room temperature, that is, it is not subjected to any additionalheating, whereby its correct functioning would be rendered impossible.The presence of the compensating and adjusting arrangement is intendedto solve the problem of enabling the releasing arrangement to have agreat releasing range or displacement range in spite of its smallness. Agreat releasing range of the thermal releasing devices corresponds to agreat temperature range. If the uppermost value of the temperature rangeand con- 0 sequently the entire range is selected high, this isequivalent to a small dimensioning of the releasing members or singlereleasing devices. If, for example, bimetal strips are used as releasingmembers or tripping means, they must have a very small cross-section. Inthe first place, this has the drawback that the danger arises of thereleasing devices burning, because they must temporarily be able toendure a very high excess current. If it is a question, for example, ofthe pro-' 40 tection of a motor having a short-circuited rotor orsquirrel-cage rotor, the releasing devices must, during the starting ofthe motor, withstand 10 to 15 times the nominal current of the motor.

On the other hand, thermal releasing devices 5 which, owing to thesmallness of their dimensions and of their cross-section, work in a veryhigh temperature range, have the drawback that they supply very smallreleasing forces. For these reasons, it is intended, in the case of thesubject of the invention, to provide releasing thermal members orthermal tripping means of relatively great dimensions which work in arelatively low temperature range. Owing to the fact that the releasingmembers in the case of the subject of the invention work in a lowtemperature range, their dependence on the room temperature is .verygreatwhich necessitates the provision of the compensating arrangement.While, as a. rule, the releasing temperatures are made very high inorder that no compensating arrangement may be necessary, in the case ofthe subject-ofthe invention only advantages are produced by working atlow releasing temperatures. The necessity of providing a compensatingarrangement does not mean any appreciable complication, on the one handbecause, in the case of the present invention, a single compensatingarrangement is used for the releasing members of all phases, and on theother hand because that chamber of the housing of the releasingarrangement which contains the compensating arrangement may be used toaccommodate other parts which are advantageously arranged in immediateproximity to the releasing members and which, as well as themselves, areto be made inaccessible to incompetent persons. Finally, the extraexpenditure necessitated by the provision. of the compensatingarrangement is of no importance considering the great adjustment rangerendered possible by the subject of the invention.

A constructional example of the invention is illustrated on a greatlyenlarged scale in the accompanying drawing, wherein Figure 1 shows alongitudinal section,

Figure 2 the constructional parts illustrated in the right-hand part ofFigure l, on a still larger scale,

Figure 3 a side view associated with Figure 2, wherein a number ofconstructional parts are shown in section,

Figure 4 a cross-section according to the line 4-4 of Figure 1,

Figure 5 a detail in somewhat modified form in section, and

Fig. 6 is a perspective of a detail.

The housing A 'of the releasing arrangement is subdivided by partitionsB into the three chambers C and the fourth chamber D. The

chambers C serve to accommodate three thermal means of an electriccurrent flowing through the strips and an indirect heating by heatingwindings wound round the bimetal Strip are known. The indirect heatingis more advantageous per se, because by corresponding dimensioning ofthe heating winding that heating can be produced which is particularlydesired, without depending on the resistance of the bimetal material.However, heating windings wound round the bimetal strip prevent thestrip from bending out, wherein resides a considerable drawback of theindirect heating by such windings. This drawback is obviated in the caseof the present invention by providing in the centre of the bimetal stripE a heating winding F concentric in' relation thereto, this windingbeing, for example, helical.

By the insertion of difierent heating windings, namely those having adifferent number of turns d consisting of difierent material, thebimetal strip E can be heated in the most manifold manrangement andtheir free ends are current-conductively connected with the bimetalstrips E which they surround. By this arrangement, it is brought aboutthat the free ends of the heating windings and consequently theirconnection with the bimetal strips is easily movable. The ends of theheating windings F are connected to the current-connection bars G which,in their turn, are secured to the housing A. The circuit of thereleasing devices runs from the bars G through the heating windings Fand the bimetal strips E to the current-connection bars H whichcarry'the' bimetal strips. All bimetal strips E act on the commonreleasing cross-member I and displace it to the right with increasingheating. The cross-member 8 passes through apertures P in the partitionsB separating the individual chambers C, D from one another.

The bimetal strip l of the compensating arrangement situated in thechamber D is sub- -stantially bent in a circle and mounted rotat-' ablyabout the concentric axis 2. Owing to the substantially circular curve,the strip is caused to execute great deflections while occupying verylittle space. As all other parts of the arrangement are grouped aboutthe bimetal strip having a substantially circular or U-shape, the spaceoccupied by the entire arrangement is very small. The bimetal strip l.is mounted through the medium of a supporting member-3 in the form of abell-crank lever on the axis 2 with which the helical spring 4 engages.The bell-crank lever 3 is a metal stamping, having an arm 3b I bent atright angles to the body portion thereof, along the line 1'. The arm 31)constitutes a support for one end of the bimetal strip I, the bi-- metalstrips being held thereon by means of screws or rivets, as shown inFigs. 2, 3, and 6. A lower extension 3a of the arm 3b carries thecontact member B. The spring I presses one of the two ends of thebimetal strip against a stop 5. On the opposite end of the bimetalstrip, which is freely movable by temperature warping, a releasingmember 6 is rotatably mounted about the axis I. The releasing ortripping devices arranged withinthe chambers C and whose dependence onthe room temperature is to be compensated, act on the releasing memberby means of the cross member 8. When the cross member 8 encounters thereleasing member 6, it rotates the member 6 together with the bimetalstrip I and the supporting member 3 in the anti-clockwise directionabout the shaft 2, whereby the tension of the spring I is increased. Thedistance between the point of the strip or crossmember 8 and thereleasing member 6, i. e. the releasing path, must not, upon fluctuationof the room temperature, be altered or only to a very small extent.Under conditions otherwise remaining constant, the releasing memberspress the strip or cross-bar 8 to the right with increasing roomtemperature, while with decreasing room temperature it is displaced tothe left. The bimetal strip I also subjected to the influence of theroom temperature displaces the releasing member to the right when theroom temperature rises and to the left when the room temperature drops.Consequently, the movement ofthe releasing members and the crossbarrespectively and that of the compensation strip I in the same directionwhich is necessary for the compensation of the influence of the roomtemperature, takes place. The movement, however, must not only be in thesame direction, but must also be equal in magnitude. This requirementcan suitably be fulfilled by selecting corresponding dimensions. Itsfulfillment, however, is most conveniently effected if the compensationbimetal strip I is given the same shape as the releasing bimetal stripsE.

With a view to arbitrarily adjusting the releasing path to correspond tothe desired intensity of the releasing current, the adjusting member 9is provided, by which the releasing member Ii can be rotated about itspoint I, at which it is articulated to the bimetal strip I, irrespectiveof the movement of the bimetal strip I by which it is carried. In thecase of the embodiment illustrated in the drawing, the releasing member6 is formed by a two-sided lever, on one side of which the releasingmember or members whose dependence on the room temperature is to becompensated act through the medium'of the strip or cross-member 8. Theadjusting member 9 is mounted rotatably about the rotational axis 2 ofthe bimetal strip I. Its upper end passes through a slot provided in thehousing III of the arrangement. The upper side of the housing III isprovided with a scale not shown in the drawing. In order to be able tofix the position of the adjusting member 9 with its aid. this adjustingmember is provided with a slot 9a which acts in the manner of anindicator. The side of the releasing member 5 facing towards theadjusting member 9 is articulated to the adjusting member, whereby it isrendered possible to rotate the releasing member and the adjustingmember together about their axes I and 2 respectively. This articulationis, for example, constituted by a guide slot in which is arranged a'pin.According to Figures 1 and 2, the releasing member 6 is provided with aslot to in which is guided a pin 9b secured to the adjusting member 9.However, the adjusting member might be provided with a slot and thereleasing member with a pin guided therein.

In the position assumed by the members 6 and 9 in Figures 1 and 2, thereleasing path of the releasing members or of the strip or cross-member8 has the greatest possible value. If the adjusting member 9 is turnedabout the axis 2 in the clockwise direction, the releasing path isreduced, because in this case the releasing member 6 is turned about theaxis 1 in the clockwise direction. If the strip or cross-member 8encounters the releasing member 6 the latter must carry out a movement sitable for initiating the releasing operation, but the position of theadjusting member 9 must not change while this is taking place. In orderto prevent this, such frictional conditions must exist that the member 8can only be driven by the member 9 but not, inversely, the member 9 bythe member 8 when the strip or cross-member 8 encounters the latter.This condition may readily be complied with if the member 9 is somounted that, owing to the presence of great frictional forces, it canonly be turned about the axis 2 with difliculty, and if the bimetalstrip be so arranged as to turn easily about the axis 2. Under thispre-supposition, when the strip or cross-member 8 encounters the member6 the bimetal strip I will be turned about the axis 2 in theanti-clockwise direction, the tension of the spring 4 being increased,but the member 9 will remain at rest.

In order to create the necessary frictional conditions, the supportingmember 3 is loosely mounted on the axis 2, so that it may be easilyrotated about this axis together with the bimetal strip I and thereleasing member Ii. In this case, it is only necessary to overcome theforce of the weak helical spring 4. The member 9 is so connccted withthe'axis 2 that upon rotation of the member 9, the axis 2 turns with it.The shaft 2 is mounted at one end in the current-connection bar II. Thepin 2a passes transversely through the shaft 2. Between the pin 2a andthe bar II is arranged a leaf spring I2 as may be seen from Figure 3.Owing to the fact that the leaf spring I2 presses on the pin 2a, therotation of the shaft 2 and consequently that of the member 9 issubjected to a certain resistance, which prevents a shifting of themember 9 when the strip or crossmember 8 encounters the member 6. Theshaft 2 rests with a collar 2b against the bar II (Figure 3).

When the bimetal strip I lies against the stop 5, a contact member I3movable with the bimetal strip I touches a stationary contact member I4co-operating with it. When the strip or crossmember 8 encounters themember 6 this latter is rotated in the anti-clockwise direction togetherwith the ,birn'etal strip I and the contact member I 3, whereby thecontact member I 3 is raised from the contact member I4, and thus breaksthe circuit which was previously closed by the contact members I3 andI4. The contact members I3 and I4 are suitable for controlling a circuitin which instantaneous breaking, i. e. breaking of short duration, is totake place. When the strip 8 is shifted again to the left after thecircuit has been broken (Figures 1 and 2) the constructional parts I, 3,6, and I3 are turned under the influence of the spring 4 about the axis2 in the clockwise direction, so that the contact members I3 and I4 cantouch each other again.

In some cases there is not required a temporary interruption of shortduration, but permanent interruption of the circuit should be effected,as by means of the co-operating contact members I5 and I6. the contactmember I6 movable together with a locking member I! which is latchedwith the supporting member 3 of the bimetal strip I. The locking memberI! is adapted to turn about the -axis I8 which passes out of the housingIII at its rear side (Figure 3). The force of the spring 4 engages withthe locking member II eccentrically in relation to its axis of rotationI8, this force pressing the bimetal strip I against its stop 5.

In the position of the parts shown in Figures 1 and 2, the contactmembers I5 and I6 touch each other. When the strip or cross-member 8encounters the member Ii, the bimetal strip I is turned together withthe supporting member 3 about the axis 2 in the anti-clockwisedirection. If the stroke of the strip or cross-member 8 is sufl'icientthe latching between the parts 3 and I1 is released. After release ofthe latching the locking member I1 turns about the axis I8 under theinfluence of the force of the spring 4 in the anti-clockwise direction,whereby the contact member I6 is lifted from the contact member I5. Thecontact members I5 and I6 remain pennanently separated from one anothereven when the strip or cross-member 8 .is returned into its ini- Thecontact member I5 is stationary and I tial position owing to the coolingof the releasing devices by which it was moved. The contact members Itand I6 are not brought into contact again until the latching between theconstructional parts 3 and I1 is re-established by rotation of the axisIt in the clockwisedirection. This may take place through the provisionof a special actuating member connectedwith the axis l8. On the otherhand, the latching of the parts I and H can automatically be efiected bythe movement of a switch member adapted for this purpose.

The contact members l3 and I6 are connected by means of the bar I I withone pole oi! the circuit to be controlled. In the topoi the housing Ill,two terminals l9 and 20 are provided, the iormer beingcurrent-conductively connected with the contact member I 4 and thelatter with the contact member IS. The second pole of the circuit to becontrolled is, according to choice, connected to the terminal I9 or tothe terminal 20, this depending on whether breaking of short duration orpermanent breaking of the circuit to be controlled is desired.

A third instance 01 releasing which comes into question in practice isthe purely mechanical releasing, for example the mechanical opening ofthe locking mechanism of an automatic switch. The present invention isalso suitable for this case, where, by means of the axis ll of themember II, the force of the spring 4 expanding upon the unlatching oithe supporting member I and of the member I! is transferred to thelocking mechanism of the switch-to be controlled.- In this case, thespring 4 forms a power accumulator common to all releasing devicesacting on the strip or cross-member I.

According to the more schematical Figure 5, the heating winding F of thebimetal strip E at the same time forms the exciting winding of themagnet system K which serves for the electromagnetic release. Thearmature M rotatable about the axis L normally in relation to the paperplane acts, as well as the bimetal strip E, on the releasing strip orcross-member I. In the case or thermal and electromagnetic release,releasing members of the type illustrated in Figure 5 are placed in allphases.

The transverse strip or cross-member l ought to be made 01. insulatingmaterial as well as the housing and the partitions subdividing the same.

I claim:-

1. In a releasing arrangement for electricadjustment of their-releasingpath, said means being arranged in the additional chamber not occupiedby a releasing member, a releasing cross-member being actuated by thereleasing members, said cross-member passing through apertures in. thepartitions-which subdivide the housing, said partitions being adapted toinsulate thermally and electrically said releasing members from eachother and from said compensating and adjusting means.

2. In a releasing arrangement for electric switches the combination of ahousing consisting of insulating material, bimetal strips bentsubstantially in the shape of an are, beating windings arrangedsubstantially in the centre ot-said bimetal strips and being envelopedby same, partitions which subdivide said housing into a plurality ofchambers whose number is greater by one than the number of said bimetalstrips provided with a heating winding, each bimetal strip and itsheating winding being accommodated in a separate chamber, means for thecompensation of the influence of the room temperature on the bimetalstrips and for the adjustment of their releasing path, said means beingarranged in the additional chamber not occupied by a bimetal strip and aheating winding, a releasing cross-member actuated by said bimetalstrips, said cross-member 1 passing through apertures in the partitionswhich subdivide the housing, said partitions being adapted to insulatethermally and electrically the elements being arranged in differentchambers.

- 3. In a releasing arrangement for electric 2 switches the combinationof a housing, bimetal strips bent substantially in the shape of an arc,heating windings arranged substantially in the centre of said bimetalstrips and being enveloped by same, partitions which subdivide said 2housing into a plurality oi chambers whose numher is greater by one thanthe number of bimetal strips provided with a heating winding, eachbimetal strip and its heating winding being accommodated in a separatechamber, means for the a compensation of the influence oi the roomtemperature. on, the bimetal strips and for the adjustment of theirreleasing path, said means being arranged in the additional chamber notoccupied by a bimetal strip being provided with a heating a winding,said means including a bimetal strip bent substantially in the shape 01an arc, a releasing cross-member being actuated by the bimetal stripsprovided with a heating coil, said cross-member passing throughapertures in the 4 partitions which subdivide the housing, saidpartitions being adapted to insulate thermally and electrically theelements being arranged in diflerent chambers.

4. In a releasing arrangement for electric 4 switches the combination oia housing, bimetal strips bent substantially in the shape of an arc,heating windings arranged substantially in the centre of said bimetalstrips and being enveloped by same, each 01 said windings co-operat- 5'ing with a magnet core with an armature to m'agnetize the same,partitions which subdivide said housing into a plurality of chamberswhose number is greater by one than the number of said bimetal stripsprovided with a heating winding, each bimetal strip and its windingbeing accommodated in a separate chamber, means for the compensation ofthe influence of the, room temperature on the bimetal strips and for theadjustment of their releasing path, said means being 6 arranged in theadditional chamber not occupied by a bimetal strip and a heatingwinding, a releasing cross-member actuated by said bimetal strips andsaid armatures, said cross-member passing through apertures in thepartitions which a subdivide the housing, said partitions being adaptedto insulate thermally and electrically the elements being arranged indiflerent chambers. 5. In -a releasing arrangement for electric switchesthe combination of a housing, bimetal 7 strips bent substantially in theshape of an arc, heating windings arranged substantially in the centreof said bimetal strips and being e'nveloped by same, said windings beingsupported at one oi their ends by said housing, their free op- 7 withthe bimetal strips by which they are surrounded, partitions whichsubdivide said housing into a plurality oi chambers whose number isgreater by one than the number of said bimetal strips provided with aheating winding, each bimetal strip and its heating winding beingaccommodated in a separate chamber, means for the compensation of theinfluence of the room temperature on the bimetal strips and for theadjustment of their releasing path, said means being arranged in theadditional chamber not occupied by a bimetal strip and a heatingwinding, a releasing cross-member actuated by said bimetal strips, saidcross-member passing through apertures in the partitions which subdividethe housing, said partitions being adapted to insulate thermally andelectrically the elements being arranged in different chambers.

6. In a releasing arrangement for electric switches the combination of ahousing consisting of insulating material, thermally acting releasingelements adapted to be heated by electric current, partitions whichsubdivide said housing into a plurality of chambers whose number isgreater by at least one than the number of releasing elements, eachreleasing element being accommodated in a separate chamber, a mechanismfor the compensation of the influence of the room temperature on thereleasing elements and for the adjustment 01 their releasing path, saidmechanism being common to all said releasing elements and arranged inthe additional chamber not occupied by a releasing element, contactmembers for opening and closing the circuit to be controlled by thereleasing elements, said contact members being accommodated in thechamber of the compensation and adjusting mecha-\ nism, a releasingcross-member being actuated by the releasing elements, said cross-memberpassing through apertures in the partitions which subdivide the housing,said partitions being adapted to insulate thermally and electricallysaid releasing elements from each other and from said compensating andadjusting mechanism.

7. In a releasing arrangement for electric switches the combination of aplurality of thermally acting releasing elements, a cross-member beingactuated by said elements, a substantially arc-shaped bimetal striprotatably mounted on a substantially concentric axis, means to exert aforce pressing one of the ends of the bimetal strip against a stop, areleasing member pivotally mounted on the opposite end of the bimetalstrip ireely movable by temperature warping, said cross-member beingadapted to act upon said releasing member, and an adjusting memberadapted to rotate the releasing member about its point of articulationto the bimetal strip irrespective of the temperature warping of saidstrip.

8. In a releasing arrangement for electric switches the combination of aplurality of thermally acting'releasing elements mounted 'on a commonsupport, walls between said elements adapted to insulate thermally andelectrically said elements from each other, a cross-member beingactuated by said elements, said cross-member passing through aperturesin the walls between said elements, a substantially arc-shaped bimetalstrip rotatably mounted on a substantially concentric axis, means toexert a force pressing one of the ends of the bimetal strip against astop, a two-sided releasing lever pivotally mounted on the opposite endof the bimetal strip movable by temperature warping, said cross-memberbeing adapted to act upon one side of the releasing lever, an adjustingmember rotatable about the axis of rotation of the bimetal strip, and aconnection between the other side of the releasing lever and theadjusting member adapted to allow the common rotation of both 'saidreleasing lever and said adjusting member about their axes of rotationby actuating said adjusting member.

9. In a releasing arrangement for electric.

switches the combination of a plurality of bimetal strips bentsubstantially in the shape of an are, means for heating said bimetalstrips by electric current, a common support for said bimetal strips,walls between said strips adapted to insulate thermally and electricallysaid strips from each other, a cross-member being actuated by saidstrips, said cross-member passing through apertures in the walls betweensaid strips, a substantialy areshaped bimetal strip rotatably mounted ona substantially concentric axis, means to exert a force torotatesaidlast mentioned strip, a stop to limit the rotation of said lastmentioned strip, a twosided releasing lever pivotally mounted on one endof the last mentioned'strip movable by temperature warping, saidcross-member being adapted to act upon one side of said releasing lever,an adjusting member rotatable about the axis of rotation of said lastmentioned strip, the other side of said releasing lever and saidadjusting member being articulated together by a slot and a pin arrangedtherein, said slot being provided in the one and said pin in the otherof both parts.

10. In a releasing arrangement for electric switches the combination ofa plurality of bimetal strips, means for heating said strips by electriccurrent, a cross-member being actuated by said strips, a bimetal stripof substantially the same shape as the before mentioned bimetal strips,said last mentioned strip being rotatably mounted on an axis through themedium of a supporting member, a rotatable locking member, a springadapted to rotate said supporting member and said locking member, a stopto limit the rotation of said supporting member, means to latch saidlocking member through the medium of said supporting member, a movablecontact member connected to said supporting member, a stationary contactmember co-operating with said movable contact member, a second movableconta'ct member' connected to said locking member, a stationary contactmember co-operating with said last mentioned contact member, a releasinglever pivotally mounted on one end of said last mentioned bimetal stripmovable by temperature warping, said cross-member being adapted to actupon said releasing lever, an adjusting lever rotatable about the axisoi. rotation of said last mentioned bimetal strip, and a connectionbetween said adjusting lever and said releasing lever adapted to allowto rotate said releasing lever about its point of articulation to thelast mentioned bimetal strip by rotating said adjusting lever.

11. In a releasing arrangement for electric switches the combination ofa plurality of bimetal strips, means for heating said strips by electriccurrent, a cross-member being actuated by' said strips, a bimetal stripof substantially the same shape as the before mentioned bimetal strips,said last mentioned strip being rotatably mounted on an axis through themedium of a supporting member, a rotatable locking member,

a spring adapted to rotate said supporting member and said lockingmember, a stop to limit the rotation. ofsaid supporting member, means toof said supporting member, a movable contact member connected to saidsupporting member, a stationary contact member co-operating with saidmovable contact member, a second movable contact member connected tosaid lockingmemher, a stationary contact member co-operating with saidlast mentioned contact member, a releasing lever pivotally mounted onone end of said last mentioned bimetal strip, a connection between saidadjusting lever and said releasing lever adapted to allowto rotate saidreleasing lever about its point of articulation to the last mentionedbimetal strip by rotating said adjusting lever a housing, partitionswhich subdivide said housing into a plurality of chambers, each bimetalstrip being accommodated in a separate switches the combination ofthermally acting releasing elements, a cross-member being actuated bysaid elements, means for the compensation of the influence of the roomtemperature on said releasing elements and for the adjustment oi theirreleasing path, a pair of co-operating contact members, means forseparating temporarily said contact members on the occurrence of apredetermined releasing movement of said crossmember, a second pair ofco-operating" contact members and means for separating permanently saidlast mentioned contact members on the occurrence of a predeterminedreleasing movement of said cross-member.

13. In a releasing arrangement for electric switches, the combination ofan insulating housing, thermally acting releasing members adapted to beheated by electric current, a winding for each releasing member andthrough which the heating electric current is adapted to flow, each ofsaid windings co-operating with a. magnet core with an armature tomagnetize the same, partitions which subdivide said housing into aplurality of chambers whose number is greater by at least one than thenumber of releasing members, each releasing member and its winding beingaccommodated in a separate chamber, ,means for compensating for theinfluence of room temperature on the releasing members and for adjustingtheir releasing path, said means being arranged in the additionalchamber not occupied by a releasing member and its winding, and areleasing cross-member adapted to be actuated by the releasing membersand said armatures, said cross-member passing through apertures in thepartitions, said partitions being adapted to 'insulate thermally andelectrically-said releasing members from each other and from saidcompensating-and-adjusting means.

ERNST BESAG.

